A Branch-and-Cut Procedure for the Vehicle Routing Problem with Time Windows

This paper addresses the problem of finding the minimum number of vehicles required to visit a set of nodes subject to time window and capacity constraints. The fleet is homogeneous and is located at a common depot. Each node requires the same type of service. An exact method is introduced based on...

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Bibliographic Details
Published inTransportation science Vol. 36; no. 2; pp. 250 - 269
Main Authors Bard, Jonathan F, Kontoravdis, George, Yu, Gang
Format Journal Article
LanguageEnglish
Published Linthicum, MD INFORMS 01.05.2002
Transportation Science Section of the Operations Research Society of America
Institute for Operations Research and the Management Sciences
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Summary:This paper addresses the problem of finding the minimum number of vehicles required to visit a set of nodes subject to time window and capacity constraints. The fleet is homogeneous and is located at a common depot. Each node requires the same type of service. An exact method is introduced based on branch and cut. In the computations, ever increasing lower bounds on the optimal solution are obtained by solving a series of relaxed problems that incorporate newly found valid inequalities. Feasible solutions or upper bounds are obtained with the help of greedy randomized adaptive search procedure (GRASP). A wide variety of cuts is introduced to tighten the linear programming (LP) relaxation of the original mixed-integer program. To find violated cuts, it is necessary to solve a separation problem. A substantial portion of the paper is aimed at describing the heuristics developed for this purpose. A new approach for obtaining feasible solutions from the LP relaxation is also discussed. Numerical results for standard 50- and 100-node benchmark problems are reported.
Bibliography:ObjectType-Article-2
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ISSN:0041-1655
1526-5447
DOI:10.1287/trsc.36.2.250.565